Pythagoras: Sometimes you don't want a specific number of pencils; you just want to be able to write something down. That's when you ask for "a pencil". Whether I give you one pencil or a box, you got what you wanted and what you asked for.
(hide) You can send a message to your friends with just one click by adding them to your friends list and then clicking the small envelope by their name. (pauloaguia) (show all tips)